as i understand it there's not going to be any new arch enemies made.
are their still arch enemy rules? Sinister Daredevil kills Sinister Bullseye....does he get double points under the new rules?

No. Archenemy rules no longer exist, and as such no extra points are given, and the previously-mentioned Daredevil and Bullseye can now team up without issue.

The feat Vendetta is there to create a "new" arch-enemy effect, if you want to (and in some official tornament you will want to) but the rule as it was has disappeared.

Cap'